Electrode boilers

ABSTRACT

In a 3-phase electrode boiler comprising a shell and three electrodes of spiral shape nested together within the shell with a spiral gap between each pair of adjacent electrodes, there is provided feed water supply means arranged to direct in the direction of the spiral gap a jet of feed water into the spiral gap between two adjacent electrodes, or preferably into the three spiral gaps between adjacent pairs of electrodes, for the purpose of flushing out of these gaps salts deposited from the boiler water. In operation the feed water jet flows along the spiral gap between two adjacent electrodes towards the center of the shell to flush out the water already there and so prevent the concentration of salts building up to an undesirably high level. The electrodes may be positioned such that the distance between adjacent electrodes progressively decreases towards the center of the spiral, thus causing the flushing jet to have a progressively increasing velocity towards the center.

United. States atent Williams Aug. 29, 1972 [54] ELECTRODE BOILERS Primary Examiner-A. Bartis [72] Inventor: Stanley Austen Williams, 10 Durl- Smker I ston Road, Poole, England 57] ABSTRACT [22] Filed: 1971 In a 3-phase electrode boiler comprising a shell and [2]] Appl. No.: 106,128 three electrodes of spiral shape nested together within the shell with a spiral gap between each pair of adjacent electrodes, there is provided feed water supply [30] Foreign App a i Pnomy Dam means arranged to direct in the direction of the spiral Jan. 27, 1970 Great Britain ..52,586/70 gap a jet of feed water into the spiral gap between two adjacent electrodes, or preferably into the three spiral [52] us. Cl. ..219/284, 219/273, 219/289, g p between adjacent pairs of electrodes, for e pu 219/291 pose of flushing out of these gaps salts deposited from 511 Int. Cl ..l-l05b 3/60 the boiler water- In Operation the e water j flows [58] Field of Search ..219/2s4-295, 271-276 along the Spiral gap between adJaCem electmdes. towards the center of the shell to flush out the water f already there and so prevent the concentration of salts [56] Re erences Clted building up to an undesirably high level. The elec- UNITED STATES PATENTS trodes may be positioned such that the distance between adjacent electrodes progressively decreases towards the center of the Spiral thus causing the flush- Smyser j to have a progressively increasing velocity 2,516,810 7/1950 Steen ..219/288 towards the cemen 1,738,733 12/1929 Schur et al ..219/284 10 Claims, 3 Drawing Figures PATENTEDAUG 29 I922 SHEET 2 BF 2 INVENTOR 01mm ELECTRODE BOILERS This invention relates to a 3-phase electrode boiler. In 3-phase electrode boilers, particularly those for generating steam, it is a usual practice to give the three electrodes a spiral shape and to nest them together within the boiler shell with adjacent electrodes separated by a spiral gap.

A disadvantage of this arrangement when the boiler is used with the electrodes only partly submerged in the water, as is also common'practice, is that the concentration of salts contained in the water in the boiler shell,

. due to evaporation as steam is formed, becomes very high in the restricted spaces between the electrodes.

The present invention seeks to provide a 3-phase electrode boiler in which the above disadvantage is avoided.

According to the invention a 3-phase electrode boiler comprising a shell and three electrodes of spiral shape nested together within the shell with a spiral gap between each pair of adjacent electrodes, is characterized by feed water supply means arranged to direct a jet of feed water into the spiral gap between two adjacent electrodes.

In operation of a boiler in accordance with the invention the feed water jet flows along the spiral gap between said two adjacent electrodes towards the center of the shell to flush out the water already there and so preventing the concentration of salts building up to an undesirably high level in the boiler water.

Preferably, further feed water supply means are arranged to direct jets of feed water into the other two spiral gaps between the electrodes.

The or each feed water supply means may take the form of a nozzle which may be mounted in a wall of the boiler shell.

The or each nozzle may be at a level located just above the lower edges of the electrodes so that when the water level in the shell is only a short distance above the lower edges of the electrodes, the incoming feed water will still flow along the gap or gaps between the electrodes. When starting up, and at certain other times, the water level may be at the level of the lower edges of the electrodes or may even be at a slightly lower level, and at these times each incoming feed water jet would form a small water bridge between the electrodes before falling into the water in the shell, but there is no disadvantage in this.

It may be found to be desirable for the or each feed water supply means to comprise a plurality of nozzles each arranged to direct a jet of feed water into the same spiral gap. The plurality of nozzles may be arranged in a vertical row. A plurality of nozzles gives more effective dilution of the water between the electrodes when the latter are immersed to any considerable extent. The

nozzle or nozzles at any one level may be connected to a different feed water supply pipe from the nozzle or nozzles at any other level so that the number of jets of feed water operative at any time can be controlled to correspond with the level of water in the boiler shell.

Normally the electrodes of a 3-phase electrode boiler are arranged with a gap of substantially constant width between adjacent electrodes, but in some instances it may be desirable to construct or position the electrodes of a boiler in accordance with the invention so that the distance between adjacent electrodes progressively decreases towards the center of the spiral. This causes the velocity of the flushing jet or jets of feed water to have a progressively increasing velocity towards the center.

One embodiment of a 3-phase electrode boiler in accordance with the invention will nowbe described, by way of example, with reference to-the accompanying drawings, in which FIG. 1 is a schematic sectional elevation of the boiler, taken on the line H of FIG. 2, and

FIG. 2 is a section taken taken along the line IIII of FIG. 1.

The electrode boiler shown in the drawings comprises a'shell, generally designated by the numeral 1, having a generally circular cylindrical wall 2, a bottom 3 formed integrally with the wall2, and a removable top 4 secured to the upper end of the wall 2.

Mounted in the top 4 are six electrically insulating bushings 5, for example of porcelain, only three of which are visible in FIG. 1. Electrode support rods 6, which may be made of cast iron, depend from these bushings.

Secured to the lower ends of the support rods 6, by means of screw-threaded connection members 7 are electrodes 8, 9 and 10, each electrode being connected to a different pair of the support rods 6. These electrodes are of spiral shape and are nested together as shown in FIG. 2 so that there are spiral gaps ll, 12 and 13 between the electrode pairs 8 and 9, 9 and 10 and 10 and 8, respectively. The nested electrodes, which may be made of cast iron, are surrounded by a sleeve formed neutral shield 14 which is secured to the top 4 of the shell by support members 15. The electrodes 8-10 are connected to the three phases of a 3-phase, 4- wire supply (not shown) by terminal rods 16 connected to the support rods 6 in the bushings 5. The neutral wire of the 3-phase supply may be connected to the shield 14.

Three feed water supply means in the form of nozzles 17, 18 and 19 are mounted in the wall 2 of the boiler shell. These nozzles project through apertures 20 in the shield 14 and have outlets 21, 22 and 23, respectively, which are arranged to direct a jet of feed water into the gaps I1, 12 and 13, respectively, just above the level of the lower edges of the electrodes. These three nozzles are connected together, either inside the boiler shell or, as shown, externally of the boiler shell, by a pipe 24 to which feed water may be supplied by a supply pipe 25. The nozzles 17, 18 and 19 may also serve for bleeding water periodically from the boiler shell and in this case the pipe 24 would be provided with a drain pipe 26 for the discharge of the water bled from the shell. The pipes 24, 25 and 26 may be connected together by a 3- way valve 27 by means of which the nozzles may either be disconnected from the pipes 25 and 26 or connected to one or other of these pipes. Operation of the valve 27 may be controlled by any suitable power-driven actuating mechanism (not shown). This actuating mechanism may be controlled automatically in dependence upon the value of a variable quantity of the boiler. For example, the current flowing to the electrodes 8-10 will vary according to the depth of immersion of the electrodes in the water in the shell. The level FIG. 3 shows a modification of the electrodes in FIG.

measuring the current flowing to the electrodes, for example employing a current transformer. The output of this current transformer may be employed to control operation of the valve-actuating mechanism.

The nozzles 17, 18 and 19 may be simple "pipes.

passing through the shell 1 and welded to the latter. Preferably, however, the nozzles are removably mounted in the boiler shell, as shown in FIG. 1, to facilitate periodical cleaning of the nozzles. From FIG. 1 it will be seen that the nozzle 17 consists of a pipe 28 which is removably mounted in a sleeve 29 which passes through the shell 1 and is welded to the latter. Externally of the shell, the sleeve 29 has a screwthreaded end on which is threaded an internally screwthreaded annular member 30. The outer end of the member 30 is externally screw-threaded to reserve a nut 31. A flange 32 on the pipe 28 is clamped in a pressure-tight manner against the outer end of the member 30 by the nut 31. v

If desired further feed water nozzles may be arranged at levels above the nozzles 8, 9 and 10, two such further nozzles being shown in chain lines in FIG. 1 where they are designated by the numerals 33 and 34. Such further nozzles would be provided for directing jets of feed water into each of the gaps 11, 12 and 13 and would be connected to further feed water supply pipes (not shown).

In the boiler shown in the drawings, thespiral gaps being arranged to direct a jet of the liquid substantially Ill, 12 and 13 have a substantially constant width throughout their length. If desired the width of these gaps may progressively decrease in the direction towards the center of the shell. This may be done by suitable dimensioning of the electrodes and/or by suitably choosing the spiral shape of each electrode. The latter modification is shown in FIG. 3.

What is claimed is:

l. A boiler comprising a closed shell having an outlet at an upper portion of said shell; at least two adjacent electrodes of spiral shape nested together within said shell with at least one spiral gap between said adjacent electrodes; supply means for feeding an electrically conductive liquid into the shell, said supply means in the direction of said spiral gap into the gap between said at least two adjacent electrodes; and connecting means to connect each electrode to a source of electrical energy to permit a flow of current through the liquid from one electrode to an adjacent electrode.

2. A boiler as defined in claim 1, having three electrodes, and wherein said connecting means connect each electrode to a different conductor of a threephase alternating current power source.

3. A boiler as defined in claim 2, in which further supply means are provided for directing jets of the liquid into each of the other spiral gaps in substantially the direction of the respective gaps.

4. A boiler as defined in claim 1, wherein said one spiral gap has an inlet, opening, and said supply means is positioned adjacent to said inlet opening and upstream of said one spiral gap.

5. A boiler as defined in claim 1, wherein said supply means comprises a nozzle.

6. A boiler as defined in claim 1, wherein said spiral %?mls o%. l%2% $i3rllio fi zl' 32c iiliniti t' direct a jet of liquid substantially in a direction of said opening at spaced points along the latter.

7. A boiler as defined in claim 1, wherein said supply means comprises a nozzle mounted in a wall of said shell.

8. A boiler as defined in claim 1, wherein said supply means comprises a nozzle; and said electrodes comprise plates of spiral configuration extending in a substantially vertical direction and having a lower edge, said nozzle being located above the lower edge of said electrodes.

9. A boiler as defined in claim 1, wherein said electrodes are of spiral shape and have increasingly smaller radii of curvature towards the center of the spiral, whereby said spiral gap between each pair of adjacent electrodes decreases progressively in the direction towards the center of the spiral.

10. A boiler as defined in claim 1, wherein said supply means includes means capable of bleeding water from the boiler. 

1. A boiler comprising a closed shell having an outlet at an upper portion of said shell; at least two adjacent electrodes of spiral shape nested together within said shell with at least one spiral gap between said adjacent electrodes; supply means for feeding an electrically conductive liquid into the shell, said supply means being arranged to direct a jet of the liquid substantially in the direction of said spiral gap into the gap between said at least two adjacent electrodes; and connecting means to connect each electrode to a source of electrical energy to permit a flow of current through the liquid from one electrode to an adjacent electrode.
 2. A boiler as defined in claim 1, having three electrodes, and wherein said connecting means connect each electrode to a different conductor of a three-phase alternating current power source.
 3. A boiler as defined in claim 2, in which further supply means are provided for directing jets of the liquid into each of the other spiral gaps in substantially the direction of the respective gaps.
 4. A boiler as defined in claim 1, wherein said one spiral gap has an inlet opening, and said supply means is positioned adjacent to said inlet opening and upstream of said one spiral gap.
 5. A boiler as defined in claim 1, wherein said supply means comprises a nozzle.
 6. A boiler as defined in claim 1, wherein said spiral gap has an elongated inlet opening and said supply means comprises a plurality of nozzles each arranged to direct a jet of liquid substantially in a direction of said opening at spaced points along the latter.
 7. A boiler as defined in claim 1, wherein said supply means comprises a nozzle mounted in a wall of said shell.
 8. A boiler as defined in claim 1, wherein said supply means comprises a nozzle; and said electrodes comprise plates of spiral configuration extending in a substantially vertical direction and having a lower edge, said nozzle being located above the lower edge of said electrodes.
 9. A boiler as defined in claim 1, wherein said electrodes are of spiral shape and have incrEasingly smaller radii of curvature towards the center of the spiral, whereby said spiral gap between each pair of adjacent electrodes decreases progressively in the direction towards the center of the spiral.
 10. A boiler as defined in claim 1, wherein said supply means includes means capable of bleeding water from the boiler. 